the soil does warm up very well… we had some hot days… a very few, I think the heat is latent heat, and the wet soil is insulating it. kind of like those geothermal wells that have been installed for cooling and heating of buildings. One of the local high schools, Roosevelt, is having the wells installed before remodeling. I think quite a few schools here in town will have that done. North should be interesting because it was built on swampy ground near the river. It is the one that was in the paper, flooded last June.